docs: def write(self, filename, content, overwrite=False):
          '''
          Write content to a file.
  
          :param str filename: The storage root-relative filename
          :param content: The content to write in the file
          :param bool overwrite: Whether to wllow overwrite or not
          :raises FileExists: If the file exists and `overwrite` is `False`
          '''
          if not self.overwrite and not overwrite and self.backend.exists(filename):
              raise FileExists()
          return self.backend.write(filename, content)